Landing an aircraft on an aircraft carrier is a very demanding task. Current aircraft carrier landing systems do not try to estimate ship parameters as they assume that ship state data is available, and does not have to be estimated. Future aircraft carrier landing systems, such as the Joint Precision Approach and Landing System (JPALS) and the Navy Unmanned Combat Air System (UCAS) will employ Global Positioning System (GPS) data from the ship and aircraft, in combination with high rate ship and aircraft state data (e.g., 20 Hz or higher rate).
When a datalink is involved, such as for JPALS or Navy UCAS, the possibility always exists that the uplink to the aircraft may be lost. If the ship to aircraft datalink is not available for the critical final few seconds of the landing, it may not be possible to continue the landing safely. For example, loss of the ship to aircraft datalink during the final 10-12 seconds of a JPALS-type aircraft carrier landing could result in a waveoff or, when waveoff is no longer an option (within the final 5 seconds), loss of the aircraft.